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Changing Climate May Substantially Alter Maple Syrup Production

Posted by Robert H. Westover, U.S. Forest Service in Forestry
Feb 21, 2017
Maple leaves of many colors offer an unending palette of color in the United States Department of Agriculture, U. S. Forest Service, Hiawatha National Forest on the Upper Peninsula of Michigan.
Maple leaves of many colors offer an unending palette of color in the United States Department of Agriculture, U. S. Forest Service, Hiawatha National Forest on the Upper Peninsula of Michigan.

U.S. Forest Service research indicates that climate change will affect habitat suitability for maple trees, threatening the multimillion dollar maple syrup industry. Changes in climate have already had an impact on the iconic sugar maple trees of the Northeastern U.S.

Flow of maple sap, which is boiled down to make syrup, is controlled by alternating freezing and thawing cycles in the late winter. Maple trees also rely on snowpack during this time to protect their roots from freezing.

Climate stressors may decrease the availability of maple syrup or shift production northward by the end of the next century because of direct changes in temperature, decreases in snowpack or increases in weather disturbances such as ice storms.

"Climate change will produce winners and losers geographically. Folks who retrieve sap from maple trees in the far Northeastern region will get a longer sap flow season while those in the Southeastern regions will see a reduction," said Dave Cleaves, Climate Change Advisor for the Forest Service.

A study conducted by the Forest Service and Cornell University examined the relationships between sugar maple sap flow and temperature over the last several decades, and used climate models to project sap flow into the future. The researchers found that the number of sap flow days may not change in the Northeast, but the timing of peak production will shift earlier.

By adapting to an earlier tapping season, maple syrup producers in Vermont and other northern states may be able to sustain their livelihoods for the next 100 years. However, at the southern extent of sugar maple habitat, such as Pennsylvania, overall production may be reduced sooner.

The Forest Service has developed an atlas of potential future habitat for 134 tree species in the Eastern United States. The atlas shows that climate change will likely reduce the amount of suitable habitat for maple trees in the coming century. While maple trees won't necessarily vanish from the landscape, there could be fewer trees that are more stressed, further reducing maple syrup availability.

Category/Topic: Forestry

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Kip Kolesinskas
Sep 11, 2012

Soil survey information and GIS analysis can be used to help find the most suitable and resilient site for future sugar bushes, especially at the edge of their range. Understanding soil landscapes will be critical to climate change adaptation strategies for agriculture and land use planning.

Timothy Perkins-UVM PMRC
Oct 29, 2014

It is important to note that shifts in the timing of tapping and improvements in sanitation practices have greatly increased the length of time that maple producers can collect sap. Yields have actually increased tremendously due to sanitation and vacuum technology improvements over the past ten years. In addition, since the spring maple season is shifting earlier in the calendar year, and if we assume that the fall sap flow season (few people tap in the fall presently) is also shifting, but towards a time later in the calendar year, it is possible that at some point these two disjunct seasons will merge to form one very long season.

Hinckley buzzard
Jun 17, 2015

Now it is 2015-- and syrup production has reached a new high. The production from the Northeast was down a bit--due to cold weather, not warming. But overall the national production was up 6%.

Richard A. Olson
Apr 01, 2020

Concerning "Climate Change" assume you are referring to Warming? According to NASA's MSU
satellite atmospheric temperature measurements there has been no significant warming since
1998 except for a blip during the Super El Nino of 2015-2016. Average satellite and balloon data
from Feb., 2016-Feb., 2018 showed a decline of -0.56 deg C. Surface temperature data from USCRN have shown no statistically significant warming since 2005 when initiated. US
temperature average for 2019 was cooler than 2005. HadCRUT4.6 showed 30-year climate change of +0..29 deg C thru Feb. 2018 reportedly during the 1978-1998 Global Warming (Global
Cooling during 1940-1978 was -0.60 deg C). According to scientists who study natural causes of
climate change there is empirical evidence of a coming Global Cooling - a Grand Solar Minimum
(NASA agrees). Please refer to the Dalton Minimum (1790-1830) or even colder Maunder
Minimum (1645-1715). Based on Solar Magnetic Field and Solar Irradiance, Zharkova et. al.
(2019) projects it will occur during 2020-2055 . We'll see. Meantime we are better off not
confusing weather with climate.